In conventional technologies, the driving system of a liquid crystal display device uses a timing controller to read the codes written in a read-only memory to perform certain control techniques, such as timing, dimming, over-driving and gamma correcting, to a liquid crystal panel. In order to facilitate the manufacturing efficiency of the hardware of the driving system, manufacturers usually write codes into the foregoing read-only memory in advance, and mount the read-only memory with other components onto the surface of a printed circuit board by using SMT or DIP technologies, and then check the codes when performing an electrical tests to the printed circuit board in the end.
How, during the foregoing mounting process of the printed circuit board, the timing controller of the printed circuit board after mounting may read wrong codes due to environmental disturbances, mechanical properties or human errors, such that the display device may wrongly display, or even unable to display. Therefore, performing a code checking step is important after the mounting of the printed circuit board.
With reference to FIG. 1, which is a flow chart of code writing and checking for a read-only memory of a printed circuit board according to the prior art, disclosing steps of: firstly writing codes to EEPROM (Electrically-Erasable Programmable Read-Only Memory) (step 90); then reading the check sum of the written codes (step 91); checking if the checksum is correct (step 92); if correct, then finishing check (step 93); if not, and then re-writing the codes (step 94). The conventional checking method needs to combine some fixtures and a computer, use a probe of the fixtures to contact a plurality of auxiliary writing points of the printed circuit board, cooperate with the computer operated by software to read the written codes, calculate the checksum, and then check if the checksum of the written codes is equal to the checksum of original codes. If they were not equal, then the codes have to be written via the writing points.
Since the conventional checking method needs to combine the computer and the fixtures to perform one-by-one operation with the probe, and then read the result from the software. Not only the work time is increased, the stability of the fixture and the software may also affect the checking result.
Hence, it is necessary to provide a code checking method for a memory of a printed circuit board to overcome the problems existing in the conventional technology.